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    <div class="refentry" id="glEnable">
      <div class="titlepage"/>
      <div class="refnamediv">
        <h2>Name</h2>
        <p>glEnable — enable or disable server-side GL capabilities</p>
      </div>
      <div class="refsynopsisdiv">
        <h2>C Specification</h2>
        <div class="funcsynopsis">
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glEnable</strong>(</code>
              </td>
              <td>GLenum <var class="pdparam">cap</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
        </div>
        <div class="funcsynopsis">
          <table style="border: 0; cellspacing: 0; cellpadding: 0;" class="funcprototype-table">
            <tr>
              <td>
                <code class="funcdef">void <strong class="fsfunc">glDisable</strong>(</code>
              </td>
              <td>GLenum <var class="pdparam">cap</var><code>)</code>;</td>
            </tr>
          </table>
          <div class="funcprototype-spacer"> </div>
        </div>
      </div>
      <div class="refsect1" id="parameters">
        <h2>Parameters</h2>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term">
                <em class="parameter">
                  <code>cap</code>
                </em>
              </span>
            </dt>
            <dd>
              <p>
                    Specifies a symbolic constant indicating a GL capability.
                </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1" id="description">
        <h2>Description</h2>
        <p>
            <code class="function">glEnable</code> and
            <a class="citerefentry" href="glDisable.xhtml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a>
            enable and disable various capabilities. Use
            <a class="citerefentry" href="glIsEnabled.xhtml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>
            or
            <a class="citerefentry" href="glGet.xhtml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
            to determine the current setting of any capability. The initial
            value for each capability with the exception of
            <code class="constant">GL_DITHER</code> is <code class="constant">GL_FALSE</code>.
            The initial value for <code class="constant">GL_DITHER</code> is
            <code class="constant">GL_TRUE</code>.
        </p>
        <p>
            Both <code class="function">glEnable</code> and <a class="citerefentry" href="glDisable.xhtml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> take a single argument, <em class="parameter"><code>cap</code></em>,
            which can assume one of the following values:
        </p>
        <div class="variablelist">
          <dl class="variablelist">
            <dt>
              <span class="term">
                <code class="constant">GL_BLEND</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        blend the computed fragment color values with the values in the color
                        buffers. See <a class="citerefentry" href="glBlendFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_CULL_FACE</code>
              </span>
            </dt>
            <dd>
              <p>
                </p>
              <p>
                        If enabled,
                        cull polygons based on their winding in window coordinates.
                        See <a class="citerefentry" href="glCullFace.xhtml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_DEPTH_TEST</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        do depth comparisons and update the depth buffer. Note that even if
                        the depth buffer exists and the depth mask is non-zero, the
                        depth buffer is not updated if the depth test is disabled. See
                        <a class="citerefentry" href="glDepthFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a> and
                        <a class="citerefentry" href="glDepthRangef.xhtml"><span class="citerefentry"><span class="refentrytitle">glDepthRangef</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term"><code class="constant">GL_DITHER</code>    </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        dither color components or indices before they are written to the
                        color buffer.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_POLYGON_OFFSET_FILL</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled, an offset is added to depth values of a polygon's
                        fragments before the depth comparison is performed.
                        See <a class="citerefentry" href="glPolygonOffset.xhtml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_PRIMITIVE_RESTART_FIXED_INDEX</code>
              </span>
            </dt>
            <dd>
              <p>
                        Enables primitive restarting.  If enabled, any one of the draw commands
                        which transfers a set of generic attribute array elements to the GL will restart
                        the primitive when the index of the vertex is equal to
                        <math overflow="scroll">
                                <msup>
                                    <mn>2</mn>
                                    <mi>n</mi>
                                </msup>
                                <mo>−</mo>
                                <mn>1</mn>
                            </math>
                        where <span class="emphasis"><em>n</em></span> is 8, 16 or 32 if the type is
                        <code class="constant">GL_UNSIGNED_BYTE</code>,
                        <code class="constant">GL_UNSIGNED_SHORT</code>, or
                        <code class="constant">GL_UNSIGNED_INT</code>, respectively.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_RASTERIZER_DISCARD</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled, primitives are discarded immediately before the rasterization stage,
                        but after the optional transform feedback stage.
                        <a class="citerefentry" href="glClear.xhtml"><span class="citerefentry"><span class="refentrytitle">glClear</span></span></a> and
                        <a class="citerefentry" href="glClearBuffer.xhtml"><span class="citerefentry"><span class="refentrytitle">glClearBuffer</span></span></a>* commands
                        are also ignored.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_SAMPLE_ALPHA_TO_COVERAGE</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        compute a temporary coverage value where each bit is determined by the
                        alpha value at the corresponding sample location.  The temporary coverage
                        value is then ANDed with the fragment coverage value.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_SAMPLE_COVERAGE</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        the fragment's coverage is ANDed with the temporary coverage value.  If
                        <code class="constant">GL_SAMPLE_COVERAGE_INVERT</code> is set to <code class="constant">GL_TRUE</code>, invert the coverage
                        value.
                        See <a class="citerefentry" href="glSampleCoverage.xhtml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_SAMPLE_MASK</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled, the fragment's coverage is ANDed with the coverage value <code class="constant">GL_SAMPLE_MASK_VALUE</code>. 
                        See <a class="citerefentry" href="glSampleMaski.xhtml"><span class="citerefentry"><span class="refentrytitle">glSampleMaski</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_SCISSOR_TEST</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        discard fragments that are outside the scissor rectangle.
                        See <a class="citerefentry" href="glScissor.xhtml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>.
                    </p>
            </dd>
            <dt>
              <span class="term">
                <code class="constant">GL_STENCIL_TEST</code>
              </span>
            </dt>
            <dd>
              <p>
                        If enabled,
                        do stencil testing and update the stencil buffer.
                        See <a class="citerefentry" href="glStencilFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a> and <a class="citerefentry" href="glStencilOp.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>.
                    </p>
            </dd>
          </dl>
        </div>
      </div>
      <div class="refsect1" id="errors">
        <h2>Errors</h2>
        <p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>cap</code></em> is not one of the values
            listed previously.
        </p>
      </div>
      <div class="refsect1" id="associatedgets">
        <h2>Associated Gets</h2>
        <p>
            <a class="citerefentry" href="glIsEnabled.xhtml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>
        </p>
        <p>
            <a class="citerefentry" href="glGet.xhtml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        </p>
      </div>
      <div class="refsect1" id="versions">
        <h2>API Version Support</h2>
        <div class="informaltable">
          <table style="border-collapse: collapse; border-top: 2px solid ; border-bottom: 2px solid ; border-left: 2px solid ; border-right: 2px solid ; ">
            <colgroup>
              <col style="text-align: left; "/>
              <col style="text-align: center; " class="firstvers"/>
              <col style="text-align: center; "/>
              <col style="text-align: center; " class="lastvers"/>
            </colgroup>
            <thead>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; ">
                 
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; " colspan="3">
                <span class="bold"><strong>OpenGL ES API Version</strong></span>
            </th>
              </tr>
              <tr>
                <th style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>Function Name</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>2.0</strong></span>
            </th>
                <th style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.0</strong></span>
            </th>
                <th style="text-align: center; border-bottom: 2px solid ; ">
                <span class="bold"><strong>3.1</strong></span>
            </th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; border-bottom: 2px solid ; ">
                  <code class="function">glEnable</code>
                </td>
                <td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
                <td style="text-align: center; border-right: 2px solid ; border-bottom: 2px solid ; ">✔</td>
                <td style="text-align: center; border-bottom: 2px solid ; ">✔</td>
              </tr>
              <tr>
                <td style="text-align: left; border-right: 2px solid ; ">
                  <code class="function">glDisable</code>
                </td>
                <td style="text-align: center; border-right: 2px solid ; ">✔</td>
                <td style="text-align: center; border-right: 2px solid ; ">✔</td>
                <td style="text-align: center; ">✔</td>
              </tr>
            </tbody>
          </table>
        </div>
      </div>
      <div class="refsect1" id="seealso">
        <h2>See Also</h2>
        <p>
            <a class="citerefentry" href="glBlendFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>,
            <a class="citerefentry" href="glCullFace.xhtml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>,
            <a class="citerefentry" href="glDepthFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a>,
            <a class="citerefentry" href="glDepthRangef.xhtml"><span class="citerefentry"><span class="refentrytitle">glDepthRangef</span></span></a>,
            <a class="citerefentry" href="glGet.xhtml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>,
            <a class="citerefentry" href="glIsEnabled.xhtml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>,
            <a class="citerefentry" href="glPolygonOffset.xhtml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>,
            <a class="citerefentry" href="glSampleCoverage.xhtml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>,
            <a class="citerefentry" href="glScissor.xhtml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>,
            <a class="citerefentry" href="glStencilFunc.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a>,
            <a class="citerefentry" href="glStencilOp.xhtml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>,
        </p>
      </div>
      <div class="refsect1" id="Copyright">
        <h2>Copyright</h2>
        <p>
            Copyright <span class="trademark"/>© 1991-2006 Silicon Graphics, Inc.
            Copyright <span class="trademark"/>© 2010-2014 Khronos Group.
            This document is licensed under the SGI Free Software B License.
            For details, see
            <a class="link" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p>
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